Water wheel

ABSTRACT

A waterwheel made up of a number of parallel narrow circular bands, connected by spokes to a central metal axel, which is in turn mounted to a boat hull on bearings. The axel is oriented perpendicular to the long axis of the keel line. Alternative to the parallel circular bands, a narrow spiral band, supported by a central metal ring and two lateral rings is also presented. Making the supporting rings of similar size simulates a flat surface of support, while making the central ring larger than the lateral support ring simulates a “V” shaped surface of support. These narrow circular or spiral bands tend to slice through the waves resulting in a smoother ride, yet still providing enough lifting effect like a water ski. However, unlike water skis, the waterwheels rotate around an axel, which is mounted on bearings, thus considerably reducing drag and improving efficiency.

BACKGROUND OF THE INVENTION

[0001] Any boat that moves on water experiences significant friction or drag between the boat hull and the water. This drag affects the speed and distance that the boat can attain for any given power. This ultimately impacts on the cost of operating the boat. Water friction is usually directly proportional to the wetted hull surface when the boat is underway.

[0002] In order to reduce drag and improve efficiency, various modifications to boat hulls had been attempted. These include various planing hulls, cleats, fins, air injection systems, multihull designs, and a variety of hydrofoil designs. Low drag hull designs such as Lang's multistepped vented hull (U.S. Pat. No. 4,348,195), his catamaran with planing pontoons (U.S. Pat. No. 5,522,333), and Dawson's boat on skis (U.S. Pat. No. D341,352) show much promise. Similarly, various hydrofoil designs such as Hoppe's catamaran with hydrofoil (U.S. Pat. No. 4,606,291), Karney 's hydroski (U.S. Pat. No. 5,988,097) and Kelsy's lifting fin (U.S. Pat. No. 5,809,926) all attempt to reduce water drag. Although all of these designs attempt to improve efficiency by reducing the wetted hull surface, most require increased power use in order to achieve the optimum planing speeds for these devices to work properly.

[0003] Three previous inventions are of particular interest to the present invention. Von Ohain et al (U.S. Pat. No. 5,785,564) invented a watercraft with a rear mounted hydrofoil blade wheel assembly. It attempts to lift the hull at the same time propel the boat like a paddle wheel. Jones (U.S. Pat. No. 6,116,176) invented a series of rollers surrounded by a belt, and mounted on the planing surface of monohulled boats, reduces drag much like a conveyor belt. Designed primarily for monohulls, this design though potentially sound in principle, may not work so well in practice since the belt surface facing the hull may accumulate a layer of water, which can cause drag. Pinchot (U.S. Pat. Nos. 4,061,104 and 3,996,872) mounted annular rotary hydrofoils on both sides of a boat at the level of the planing surfaces, in order to reduce drag. This design, also made for monohulls, suffer from two potential problems: 1) the lifting surface is small, and 2) the side mounted design renders them prone to damage, particularly on docking.

[0004] I devised a water wheel specifically designed for multi-hulled vessels (catamarans and trimarans), whose objective is to reduce water drag by lifting part of the boats weight, reducing the hull's wetted surface area and simulating planing hulls at relatively lower speeds and power requirements.

SUMMARY OF THE INVENTION

[0005] The invention is essentially a water wheel made up of either multiple parallel mounted circular bands or spiral bands which are mounted to a central axel by spokes. The axel in turn is designed to be mounted to the inner hull surface of muli-hulled vessels on bearings. The circular and spiral bands may be made of either metal, wood, hard rubber, resin impregnated glass or carbon fiber or a combination of these materials. These circular and spiral water wheels are designed to freely rotate about their axel when the boat gets underway, thus creating a lifting effect when the boat reaches planing speed. This reduces the wetted surface of the boats hull. Since the wheels rims are either circular or spiral bands about a central axel mounted perpendicular to the forward motion of the boat, at planing speeds, these bands should support some of the weight of the boat as they skim on the water surface. Much like a narrow plank can support the weight of a water skier, the narrow bands of the water wheel tend to slice through the waves even in choppy waters, but unlike the water skier whose skis encounter considerable water friction, the water wheel rolls over the surface with less friction by virtue of their rotation and bearing mounts. These water wheels are designed to fit within the hull tunnels of multi-hulled boats. The net effect of this invention is improved efficiency, which translates to improved fuel economy, lower speeds to achieve planing, increased top speed and range, and a smoother ride.

BRIEF DESCRIPTION OF DRAWINGS

[0006]FIG. 1 shows a diagonal view of a water wheel with parallel ring bands of the same circumference attached to a central axel by spokes.

[0007]FIG. 2 shows a diagonal view of a spiral band wheel attached to a central axel by spokes.

[0008]FIG. 3 shows a frontal view of a parallel ring water wheel with equal circumference, attached to the inner hull surfaces of a catamaran. Since the ring bands are of equal size, they all touch the water surface equally thus simulating a flat bottom support.

[0009]FIG. 4 shows a frontal view of a parallel ring water wheel with ring sizes progressively diminishing from the center ring outwards, thus simulating a “v” bottom support.

[0010]FIGS. 5 and 6 show a frontal view of a flat bottom spiral wheel and a “v” bottom spiral wheel respectively. Both are shown mounted to the inner hull walls of a catamaran.

[0011]FIGS. 7 and 8 show bottom views of a bank of “v” bottom spiral water wheels and a bank of parallel ring water wheels respectively.

[0012]FIG. 9 shows a bottom view of a trimaran with banks of split “v” bottom spiral water wheels mounted.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The invention is that of a water wheel, which can be fitted onto multi-hulled boats in order to, reduce water friction or drag when the boat is planing. The wheel is composed of a central metal axel (5) designed to be mounted on the inner hull surface of multi-hulled boats, on bearings (1). The axel (5) must be oriented perpendicular to the boat's keel. One design (FIG. 1) is a series of circular bands attached to a central axel (5) by metal spokes (2). The narrow bands or rims (3) may be made either of metal, wood, hard rubber, resin-impregnated glass or carbon fiber or a combination of these materials. A number of similar rings can be mounted to the axel in parallel fashion (FIGS. 1 and 3). If the circumference of these ring bands were the same, they would contact the water surface equally, simulating the stability of a flat bottom hull but without the noise and vibration of a flat hull in wavy seas. If the central ring is larger and each succeeding lateral rings progressively get smaller (FIG. 4), the largest ring band sinks lower in the water than the smaller lateral rings thus simulating a “V” hull for better cornering and rough water cruising. The cross sectional shapes of these ring bands may be flat or shallow “V” shaped (FIG. 1 detail ). An alternative design is a spiral band (FIG. 2) wound around a centrally located axel (5) and supported by metal spokes (2). The band starts from a central mounting ring (4 a) and spirals around laterally until it anchors onto lateral rings (4 b). Two or more of this spiral bands may be needed to form the whole water wheel. The radial band cross section is shown in FIG. 2 detail. The spiral band water wheel may be made to simulate either a flat bottom support (FIG. 5) or a “V” bottom support (FIG. 6). A series or banks of these water wheels can be mounted along the length of the tunnel hull (FIGS. 7, 8 and 9), to provide more lift for heavier boats.

[0014] LEGEND

[0015]1. Bearing

[0016]2. Wheel spoke

[0017]3. Circular wheel band

[0018]4. Spiral wheel bands

[0019]4 a. Central ring support

[0020]4 b. Lateral ring support

[0021]4 c. Split “V” spiral wheel

[0022]5. Central axel

[0023]6. Boat hull 

1. I claim a waterwheel device comprising of a series of narrow circular bands mounted parallel to each other by spokes, along the length of a metal axel which is in turn connected to the inner wall of a multi-hull boat by means of bearings and is meant to rotate freely and at planing speed is designed to carry some of the weight of the boat, reduce the wetted surface of the hulls, consequently reducing drag.
 2. I claim an alternative waterwheel device comprising of two or more narrow spiral bands mounted by spokes to a metal central axel which is in turn connected to the inner wall of a multi-hulled boat by means of bearings, and is meant to rotate freely and at planing speed is designed to carry part of the weight of the boat, reduce the wetted surface of the hulls, consequently reducing drag.
 3. The device described in claim 1 wherein the narrow circular band in contact with the water is made up either of metal, wood, hard rubber, resin impregnated glass or carbon fiber, or a combination of these materials whose surface, cross-sectional profile is either flat or a shallow “V” shape.
 4. The device described in claim 1 wherein the metal axel is mounted on bearings to the boat hulls, with an orientation perpendicular to the long axis of the keel of the boat.
 5. The device described in claim 1 is positioned in such a way that the level of the lowest portion of the circular bands protrudes slightly lower than the bottom of the boats hulls.
 6. The device described in claim 1 wherein the circumference of the circular bands can either be the same, simulating a flat water support, or progressively diminishing in size from the center ring outwards to simulate a “V” shaped water support.
 7. The device described in claim 2 wherein the narrow bands are attached in spiral fashion from a central metal ring support, outwards to lateral support rings, which are fixed to the metal axel by means of spokes.
 8. The narrow band described in claim 7 originates from the central supporting ring and spirals laterally around the axel and attaches to the lateral support wheels in mirror like fashion.
 9. The device in claim 2 wherein the narrow spiral bands in contact with the water is made up of either metal, wood, hard rubber, resin impregnated glass or carbon fiber, or a combination of these materials, whose surface cross sectional profile is either flat or gently sloping inward or outward.
 10. The device described in claim 2 wherein the central and lateral wheel supports rings may either be the same circumference to simulate a flat bottom support, or that the middle ring support is bigger than the two lateral support rings, to simulate a “V” shaped bottom.
 11. A series of the waterwheel devices described in claims 1 and 2 can be mounted along the length of the boat hull for more support and level ride.
 12. The devices described in claims 1 and 2 are designed to fit within the tunnel space between the hulls of multi-hulled boats.
 13. In trimarans, a split “V” configuration of the waterwheel devices may be mounted within the two hull tunnels particularly when the central hull of the boat sits deeper in the water than the two lateral hulls. 